In home appliances such as washing machines or dish washers, liquid pumps are used to pressurize and deliver water so as to introduce clean water into the appliances for cleaning clothes or dishes, and finally discharge the waste water out of the appliances.
The existing liquid pumps usually use a single phase permanent magnet motor to drive an impeller to rotate. The motor has an stator core and a permanent magnet rotor rotatably disposed in the stator core. The stator core is wound with windings. The windings are connected to a driving circuit. Upon energization of the windings, the stator core is polarized which interacts with permanent magnet rotor to drive the rotor to rotate. The impeller is connected to the rotor for synchronous rotation with the rotor to drive the water to flow. stator core
In a conventional design, a rotor housing is disposed between the rotor and the stator core. However, when the stator core is assembled to the rotor housing, the stator core may scratch the rotor housing to produce debris. If the debris is clamped between the stator core and the rotor housing, the stator core cannot be assembled in place, which makes the axes of the stator and rotor offset from each other, thereby causing unsmooth rotation of the rotor and large noise.